Researchers have uncovered a supermassive black hole-driven quasar that may have played a role in “illuminating” the universe in its formative era.
The significant fluctuations in brightness of this quasar were detected by NASA’s NuSTAR (Nuclear Spectroscopic Telescope ARray) X-ray space observatory. The data collected by NuSTAR was then correlated with information about the same feeding supermassive black hole obtained from NASA’s Chandra X-ray space observatory.
The recent discoveries could provide insight into how the universe’s early “dark ages” came to an end and how black holes swiftly evolved to possess masses comparable to millions or billions of suns in such a remote past.
It is hypothesized that supermassive black holes become so massive through a sequence of mergers with smaller black holes and by consuming vast quantities of gas and dust. However, this process is believed to require at least a billion years. This indicates that supermassive black holes which formed less than one billion years following the Big Bang present a problem that astronomers are eager to resolve.
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The quasar under examination, labeled CFHQS J142952+54471 (J1429+5447), is situated so far away that its light has been journeying to Earth for nearly 13 billion years, placing it at the end of that perplexing epoch.
“In this research, we have identified that this quasar is very likely to be a supermassive black hole with a jet oriented towards Earth — and we are witnessing it during the first billion years of the universe,” stated study leader Lea Marcotulli, a scholar at Yale University, in a statement.
This timeline suggests that this supermassive black hole, believed to weigh around 200 million times more than the sun, existed during a crucial cosmic phase referred to as the “epoch of reionization.”
Let there be light…
The cosmic dark ages extended until roughly 1.1 billion years post-Big Bang.
At about 380,000 years after the universe’s inception, it had cooled sufficiently for electrons and protons to unite and form atoms. The extinction of free electrons allowed photons, the essential particles of light, to travel unimpeded across vast distances.
In simpler terms, the universe transitioned from opaque to transparent. A remnant of this “first light” can be observed today as the cosmic microwave background (CMB).
Nevertheless, as the universe continued to cool, more neutral hydrogen atoms were created, which began to absorb photons in great quantities, resulting in the universe becoming dark again and initiating the cosmic dark ages.
The epoch of reionization refers to the timeframe from 680 million to 1.1 billion years after the Big Bang, during which high-energy light began to strip electrons from hydrogen ions, enabling light to move freely once again.
Although it is believed that ultraviolet light from the initial stars played a crucial role in the reionization process, researchers have long theorized that there must have been additional sources of high-energy light contributing to the phenomenon.
This is where the early quasars come into the equation.
“The epoch of reionization is regarded as the conclusion of the universe’s dark ages,” remarked Thomas Connor, a scientist at the Chandra X-Ray Center, and a member of the study team. “The exact timeline and type of sources responsible for reionization are still up for debate, and aggressively accreting supermassive black holes are one proposed reason.”
Quasars clear the early cosmic haze
Quasars are observed where supermassive black holes are voraciously consuming matter in their vicinity.
These supermassive black holes create immense friction within the flattened clouds of material, known as accretion disks, that gradually feed them. Moreover, matter not consumed by the black hole is channeled to its poles, where it is expelled as near-light-speed jets.
This phenomenon makes quasars like J1429+5447 often more luminous than the total brightness of all the stars in the galaxies surrounding them across the electromagnetic spectrum.
Consequently, not only do they serve as ideal sources for investigating the end of the cosmic dark ages, but they are also prime candidates in the quest for this crucial universal phase transition, potentially supplying the energy to ionize neutral hydrogen.
Connor and his colleagues analyzed observations of J1429+5447 captured by NuSTAR alongside data from Chandra regarding the same quasar.
The investigators determined that the X-ray emissions from J1429+5447 increased twofold over a span of four months. While this duration is incredibly brief in cosmic terms within a universe that is 165.6 billion months old, the relativity-induced time distortion compresses the four months of changes for this quasar into just two weeks for this early supermassive black hole.
“Given that the jet travels at nearly the speed of light, the principles of Einstein’s theory of special relativity accelerate and magnify the variability,” explained team member Meg Urry from Yale’s Faculty of Arts and Sciences. “This degree of X-ray variability, in terms of both intensity and rapidity, is extraordinary. It is almost certainly indicative of a jet directed toward us — a cone from which particles are projected up to a million light-years away from the central, supermassive black hole.”
This observation could not only assist scientists in unraveling the mysteries of reionization but might also be essential for identifying additional early supermassive black holes and understanding their substantial growth.
“Discovering more supermassive black holes that potentially boast jets poses the question of how these black holes reached such significant proportions within a short timeframe and what the relationship could be to mechanisms that trigger jet formation,” Marcotulli concluded.
The team presented their findings at the 245th assembly of the American Astronomical Society held in National Harbor, Maryland, on Tuesday (Jan. 14). Their research was published on the same day in the Astrophysical Journal Letters.